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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1993-9-10
pubmed:abstractText
The function of the ectoenzyme NAD glycohydrolase (NADase) in ADP-ribose uptake from extracellular NAD was studied in human erythrocytes that express relatively high NADase activity (adult erythrocytes) and erythrocytes expressing very low activity (newborn erythrocytes). The rates of ADP-ribose uptake from NAD in human erythrocytes were correlated with their NADase activities. In contrast, there was no significant difference in the rates of ADP-ribose uptake among these cells when incubated with ADP-ribose. These results indicate that ecto-NADase may have a role as supplier of ADP-ribose for its uptake into the cells and that the cleavage of NAD by NADase is necessary for the ADP-ribose uptake by human erythrocytes. From ADP-ribose uptake studies at 37 degrees C a Km of 0.7 +/- 0.05 microM and a Vmax of 2.04 +/- 0.1 pmol/min per microliter cell water was found for the uptake of [3H]ADP-ribose. The thiol-reactive reagents p-chloromercuribenzene sulfonic acid and N-ethylmaleimide inhibited the uptake ADP-ribose with IC50 values of 50 +/- 4 and 750 +/- 25 mM, respectively. Since efflux of [3H]ADP-ribose was negligible, the ADP-ribose transport system appears to be unidirectional. The unidirectionality was supported by the evidence that transported ADP-ribose was rapidly degraded to AMP which is impermeable to the membrane.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0006-3002
pubmed:author
pubmed:issnType
Print
pubmed:day
18
pubmed:volume
1178
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
121-6
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1993
pubmed:articleTitle
Function of NAD glycohydrolase in ADP-ribose uptake from NAD by human erythrocytes.
pubmed:affiliation
Department of Biochemistry, Chonbuk National University Medical School, Chonju, South Korea.
pubmed:publicationType
Journal Article, In Vitro